Collagen matrix vs mitomycin-C in trabeculectomy and combined phacoemulsification and trabeculectomy: a randomized controlled trial

Abstract

Background: Antifibrotic agents are commonly utilized to enhance the success rates of trabeculectomy. Novel approaches to further improve success rates and reduce the risks of complications are needed. The purpose of this study was to compare intraocular pressure (IOP)-lowering efficacy and safety of trabeculectomy or combined phacoemulsification and trabeculectomy with mitomycin-C (MMC) vs. Collagen Matrix (CM).

Methods: A prospective, multicenter, randomized controlled trial was performed. Ninety-five eyes of 94 patients with uncontrolled glaucoma despite medical therapy, without previous incisional glaucoma surgery underwent trabeculectomy (85 eyes) or combined phacoemulsification and trabeculectomy (10 eyes) and were randomized to MMC or CM. One eye of each subject was analyzed. Patients were followed for 24 months. The criteria for complete success were IOP >5 and ≤21 mmHg with at least a 20% reduction below medicated baseline without additional glaucoma surgery or medications. The main outcome measures were complete success rates at 24 months with Kaplan-Meier analysis and incidence of adverse events.

Results: The baseline IOPs were 20.4 ± 6.0 mmHg and 21.2 ± 6.1 (mean ± standard deviation, p = 0.49) on 3.2 ± 1.1 and 3.1 ± 1.0 medications (p = 0.53) compared to 11.8 ± 5.2 and 12.8 ± 3.7 (p = 0.36) on 0.5 ± 0.8 and 0.6 ± 1.0 medications (p = 0.63) at 2 years in the MMC and CM groups, respectively. Kaplan-Meier analysis demonstrated complete success rates were similar in both groups at 24 months: 38.4 ± 7.6% with MMC and 56.2 ± 7.9% with CM (mean ± standard error, p = 0.112, log rank test); however, a significantly higher incidence of failure due to persistent hypotony was observed with MMC (p = 0.002).

Conclusions: Use of the CM implant at the time of trabeculectomy or combined phacoemulsification and trabeculectomy is associated with similar complete success rates compared to adjunctive MMC; however, the risk of persistent hypotony is higher with MMC.

Trial registration: ClinicalTrials.gov registration number NCT01440751 . Registered 9/14/11.

Figures

Fig. 1

Patient flow chart from enrollment through 24 months. Abbreviations: IOP = Intraocular Pressure; MMC = Mitomycin C; CM = Collagen Matrix

Fig. 2

Mean intraocular pressure at each study visit in the collagen matrix (CM) and mitomycin-C (MMC) groups (p > 0.05 comparing CM with MMC at all the time points). The error bars represent standard deviations. Abbreviations: IOP = Intraocular Pressure; MMC = Mitomycin C; CM = Collagen Matrix

Fig. 3

Mean percent reduction in intraocular pressure from the mean of the two baseline visits at each subsequent study visit in the collagen matrix (CM) and mitomycin-C (MMC) groups (p > 0.05 comparing CM with MMC at all the time points). The error bars represent standard deviations

Fig. 4

Mean number of ocular hypotensive medications at the baseline visit prior to surgery and each subsequent study visit in the collagen matrix (CM) and mitomycin-C (MMC) groups (p < 0.05 by Wilcoxon rank sum test at days 1 and 7).

Fig. 5

Kaplan-Meier curve demonstrating complete success rates in the collagen matrix (CM) and mitomycin-C (MMC) groups using the intraocular pressure criteria > 5 mmHg, ≤ 21 mmHg and 20% below the medicated baseline IOP

Fig. 6

Kaplan-Meier curve demonstrating complete success rates in the collagen matrix (CM) and mitomycin-C (MMC) groups using the intraocular pressure criteria > 5 mmHg, ≤ 17 mmHg with a 20% below the medicated baseline IOP

Fig. 7

Kaplan-Meier curve demonstrating overall success rates in the collagen matrix (CM) and mitomycin-C (MMC) groups using the intraocular pressure criteria > 5 mmHg, ≤ 21 mmHg with a 20% below the medicated baseline IOP with or without the use of medication at the time of the study visit

Fig. 8

Kaplan-Meier curve demonstrating overall success rates in the collagen matrix (CM) and mitomycin-C (MMC) groups using the intraocular pressure criteria > 5 mmHg, ≤ 17 mmHg with a 20% below the medicated baseline IOP with or without the use of medication at the time of the study visit

Fig. 9

Kaplan-Meier curve demonstrating hypotony-free rates in the collagen matrix (CM) and mitomycin-C (MMC) groups using the intraocular pressure criterion ≤ 5 mmHg on two consecutive visits, starting at the 6-month visit. If IOP was ≤ 5 mmHg at the final study visit, the patient was classified as having met the definition of hypotony. The risk of hypotony was significantly higher in the MMC group (p = 0.002)